Merge pull request #324 from rj03hou/replication-reset-slave

check the slave status when find recursive find the master, so suppor…

go/logic/inspect.go

@@ -692,6 +692,7 @@ func (this *Inspector) readChangelogState() (map[string]string, error) {
 }
 
 func (this *Inspector) getMasterConnectionConfig() (applierConfig *mysql.ConnectionConfig, err error) {
+	log.Infof("Recursively searching for replication master")
 	visitedKeys := mysql.NewInstanceKeyMap()
 	return mysql.GetMasterConnectionConfigSafe(this.connectionConfig, visitedKeys, this.migrationContext.AllowedMasterMaster)
 }

go/mysql/utils.go

@@ -83,12 +83,33 @@ func GetMasterKeyFromSlaveStatus(connectionConfig *ConnectionConfig) (masterKey
 		return nil, err
 	}
 	err = sqlutils.QueryRowsMap(db, `show slave status`, func(rowMap sqlutils.RowMap) error {
+		// We wish to recognize the case where the topology's master actually has replication configuration.
+		// This can happen when a DBA issues a `RESET SLAVE` instead of `RESET SLAVE ALL`.
+
+		// An empty log file indicates this is a master:
+		if rowMap.GetString("Master_Log_File") == "" {
+			return nil
+		}
+
+		slaveIORunning := rowMap.GetString("Slave_IO_Running")
+		slaveSQLRunning := rowMap.GetString("Slave_SQL_Running")
+
+		//
+		if slaveIORunning != "Yes" || slaveSQLRunning != "Yes" {
+			return fmt.Errorf("Replication on %+v is broken: Slave_IO_Running: %s, Slave_SQL_Running: %s. Please make sure replication runs before using gh-ost.",
+				connectionConfig.Key,
+				slaveIORunning,
+				slaveSQLRunning,
+			)
+		}
+
 		masterKey = &InstanceKey{
 			Hostname: rowMap.GetString("Master_Host"),
 			Port:     rowMap.GetInt("Master_Port"),
 		}
 		return nil
 	})
+
 	return masterKey, err
 }
 

localtests/trivial/create.sql

@@ -0,0 +1,13 @@
+drop table if exists gh_ost_test;
+create table gh_ost_test (
+  id int auto_increment,
+  i int not null,
+  color varchar(32),
+  primary key(id)
+) auto_increment=1;
+
+drop event if exists gh_ost_test;
+
+insert into gh_ost_test values (null, 11, 'red');
+insert into gh_ost_test values (null, 13, 'green');
+insert into gh_ost_test values (null, 17, 'blue');

localtests/trivial/extra_args

@@ -0,0 +1 @@
+--throttle-query='select false' \